Dimethyl Fumarate Alleviates Dextran Sulfate Sodium-Induced Colitis, through the Activation of Nrf2-Mediated Antioxidant and Anti-inflammatory Pathways.

Oxidative stress and chronic inflammation play critical roles in the pathogenesis of ulcerative colitis (UC) and inflammatory bowel diseases (IBD). A previous study has demonstrated that dimethyl fumarate (DMF) protects mice from dextran sulfate sodium (DSS)-induced colitis via its potential antioxidant capacity, and by inhibiting the activation of the NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasome. This study aims to clarify the nuclear factor erythroid 2-related factor 2/antioxidant responsive element (Nrf2/ARE) pathway pharmacological activation and anti-inflammatory effect by DMF, through focusing on other crucial antioxidant enzymes and inflammatory mediator, including glutamate-cysteine ligase catalytic subunit (GCLC), glutathione peroxidase (GPX) and cyclooxygenase-2 (COX-2), in a DSS-induced colitis mouse model. The oral administration of DMF attenuated the shortening of colons and alleviated colonic inflammation. Furthermore, the expression of key antioxidant enzymes, including GCLC and GPX, in the colonic tissue were significantly increased by DMF administration. In addition, protein expression of the inflammatory mediator, COX-2, was reduced by DMF administration. Our results suggest that DMF alleviates DSS-induced colonic inflammatory damage, likely via up-regulating GCLC and GPX and down-regulating COX-2 protein expression in colonic tissue.

Treatment with dimethyl fumarate ameliorates liver ischemia/reperfusion injury.

AIM: To investigate the hypothesis that treatment with dimethyl fumarate (DMF) may ameliorate liver ischemia/reperfusion injury (I/RI). METHODS: Rats were divided into 3 groups: sham, control (CTL), and DMF. DMF (25 mg/kg, twice/d) was orally administered for 2 d before the procedure. The CTL and DMF rats were subjected to ischemia for 1 h and reperfusion for 2 h. The serum alanine aminotransferase (ALT) and malondialdehyde (MDA) levels, adenosine triphosphate (ATP), NO × metabolites, anti-oxidant enzyme expression level, anti-inflammatory effect, and anti-apoptotic effect were determined. RESULTS: Histological tissue damage was significantly reduced in the DMF group (Suzuki scores: sham: 0 ± 0; CTL: 9.3 ± 0.5; DMF: 2.5 ± 1.2; sham vs CTL, P < 0.0001; CTL vs DMF, P < 0.0001). This effect was associated with significantly lower serum ALT (DMF 5026 ± 2305 U/L vs CTL 10592 ± 1152 U/L, P = 0.04) and MDA (DMF 18.2 ± 1.4 µmol/L vs CTL 26.0 ± 1.0 µmol/L, P = 0.0009). DMF effectively improved the ATP content (DMF 20.3 ± 0.4 nmol/mg vs CTL 18.3 ± 0.6 nmol/mg, P = 0.02), myeloperoxidase activity (DMF 7.8 ± 0.4 mU/mL vs CTL 6.0 ± 0.5 mU/mL, P = 0.01) and level of endothelial nitric oxide synthase expression (DMF 0.38 ± 0.05-fold vs 0.17 ± 0.06-fold, P = 0.02). The higher expression levels of anti-oxidant enzymes (catalase and glutamate-cysteine ligase modifier subunit and lower levels of key inflammatory mediators (nuclear factor-kappa B and cyclooxygenase-2 were confirmed in the DMF group. CONCLUSION: DMF improved the liver function and the anti-oxidant and inflammation status following I/RI. Treatment with DMF could be a promising strategy in patients with liver I/RI.

Synthetic Triterpenoid RTA dh404 (CDDO-dhTFEA) Ameliorates Acute Pancreatitis.

OBJECTIVES: Nuclear factor-erythroid-2-related factor (Nrf2) is a ubiquitous transcriptional factor that regulates expression of cellular antioxidant and detoxifying molecules. This study was undertaken to test the hypothesis that administration of the Nrf2 activator (dh404) may attenuate acute pancreatitis. METHODS: Rats were treated with dh404 (1 mg/kg) 24 hours before induction of pancreatitis and for 3 days thereafter. Pancreatitis was induced with L-arginine (600 mg/100 g) or cerulein (40 µg/kg). Pancreases were processed for histology and malondialdehyde, whereas serum was analyzed for amylase. Islet extracted human pancreatic tissue from organ donors were used for in vitro studies. The tissues were incubated with dh404 at 0, 250, and 500 nM for 30 minutes, 60 minutes, 12 hours, and 24 hours. Nuclear factor-erythroid-2-related factor nuclear translocation and expression of Nrf2's target genes and inflammatory mediators were determined. RESULTS: The dh404-treated rat pancreases demonstrated significantly less infiltration of inflammatory cells, destruction of acinar architecture, perilobar edema, and necrosis. Serum amylase and pancreatic malondialdehyde in the dh404-treated rats were significantly lower. dh404-treated human pancreatic tissue showed a significantly higher expression of antioxidant enzymes, lower expression of inflammatory mediators, and greater viability against oxidative stress. CONCLUSION: Administration of dh404 attenuates acute pancreatitis by lowering oxidative stress and reducing proinflammatory mediators.

The effect of Nrf2 pathway activation on human pancreatic islet cells.

BACKGROUND: Pancreatic islets are known to contain low level of antioxidants that renders them vulnerable to oxidative stress. Nrf2 is the master regulator of numerous genes, encoding antioxidant, detoxifying, and cytoprotective molecules. Activation of Nrf2 pathway induces up-regulation of numerous genes encoding antioxidant and phase II detoxifying enzymes and related proteins. However, little is known regarding the role of this pathway in human islet cells. The aim was to investigate the effect of Nrf2 activator (dh404, CDDO-9,11-dihydro-trifluoroethyl amide) on human islet cells. METHODS: Human islets were obtained from cadaveric donors. After dh404 treatment, Nrf2 translocation, mRNA expression, and protein abundance of its key target gene products were examined. The proportion of dh404-treated or non-treated viable islet beta cells was analyzed using flowcytemetry. The cytoprotective effects against oxidative stress and production of inflammatory mediators, and in vivo islet function after transplantation were determined. RESULTS: Nrf2 nuclear translocation was confirmed by con-focal microscope within 2 hours after treatment, which was associated with a dose-dependent increase in mRNA expression of anti-oxidants, including NQO1, HO-1, and GCLC. Enhanced HO-1 expression in dh404 treated islets was confirmed by Western Blot assay. Islet function after transplantation (2000 IEQ/mouse) to diabetic nude mice was not affected with or without dh404 treatment. After induction of oxidative stress with hydrogen peroxide (200 µM) the proportion of dh404-treated viable islet cells was significantly higher in the dh404-treated than untreated islets (74% vs.57%; P<0.05). Dh404 significantly decreased production of cytokines/chemokines including IL-1ß, IL-6, IFN-γ and MCP-1. CONCLUSION: Treatment of human pancreatic islets with the potent synthetic Nrf2 activator, dh404, significantly increased expression of the key anti-oxidants enzymes, decreased inflammatory mediators in islets and conferred protection against oxidative stress in beta cells.

Emerging enhanced imaging technologies of the esophagus: spectroscopy, confocal laser endomicroscopy, and optical coherence tomography.

BACKGROUND: Despite advances in diagnoses and therapy, esophageal adenocarcinoma remains a highly lethal neoplasm. Hence, a great interest has been placed in detecting early lesions and in the detection of Barrett esophagus (BE). Advanced imaging technologies of the esophagus have then been developed with the aim of improving biopsy sensitivity and detection of preplastic and neoplastic cells. The purpose of this article was to review emerging imaging technologies for esophageal pathology, spectroscopy, confocal laser endomicroscopy (CLE), and optical coherence tomography (OCT). METHODS: We conducted a PubMed search using the search string "esophagus or esophageal or oesophageal or oesophagus" and "Barrett or esophageal neoplasm" and "spectroscopy or optical spectroscopy" and "confocal laser endomicroscopy" and "confocal microscopy" and "optical coherence tomography." The first and senior author separately reviewed all articles. Our search identified: 19 in vivo studies with spectroscopy that accounted for 1021 patients and 4 ex vivo studies; 14 clinical CLE in vivo studies that accounted for 941 patients and 1 ex vivo study with 13 patients; and 17 clinical OCT in vivo studies that accounted for 773 patients and 2 ex vivo studies. RESULTS: Human studies using spectroscopy had a very high sensitivity and specificity for the detection of BE. CLE showed a high interobserver agreement in diagnosing esophageal pathology and an accuracy of predicting neoplasia. We also found several clinical studies that reported excellent diagnostic sensitivity and specificity for the detection of BE using OCT. CONCLUSIONS: Advanced imaging technology for the detection of esophageal lesions is a promising field that aims to improve the detection of early esophageal lesions. Although advancing imaging techniques improve diagnostic sensitivities and specificities, their integration into diagnostic protocols has yet to be perfected.

Treatment With Dimethyl Fumarate Attenuates Calcineurin Inhibitor-induced Nephrotoxicity.

BACKGROUND: Cyclosporine A (CsA) is an immunosuppressive drug which has been widely used to prevent rejection after organ transplantation. However, its therapeutic use is limited by nephrotoxicity, in part mediated by oxidative stress. The present study aims to investigate the protective effects of dimethyl fumarate (DMF) on CsA-induced nephrotoxicity by enhancing the antioxidant defense system. METHODS: Male Sprague-Dawley rats were treated with CsA (n = 8, 20 mg/kg per day intraperitoneally) or CsA + DMF (n = 7, 50 mg/kg per day orally) for 28 days. Renal function, histopathology, malondialdehyde (MDA), myeloperoxidase levels, and antioxidant enzyme expression were determined. RESULTS: The DMF cotreatment ameliorated CsA-induced renal dysfunction as evidenced by significant decrease in serum creatinine (CsA 0.79 ± 0.02 mg/dL vs CsA + DMF 0.62 ± 0.04 mg/dL, P = 0.001) and urea (CsA 66.9 ± 0.4 mg/dL vs CsA + DMF 53.3 ± 2.6 mg/dl, P < 0.0001) levels, as well as improvement of creatinine clearance. Dimethyl fumarate also significantly decreased serum MDA and renal tissue MDA and myeloperoxidase contents. The protein expression of NAD(P)H quinone oxidoreductase-1, a major cellular antioxidant and detoxifying enzyme, was significantly enhanced by DMF administration in kidney. CONCLUSIONS: Administration of DMF has a protective potential against CsA nephrotoxicity. The protection afforded by DMF is mediated in part through inhibiting oxidative stress and inflammation and enhancing the antioxidant capacity.

Pharmacological activation of Nrf2 pathway improves pancreatic islet isolation and transplantation.

Oxidative stress is a major cause of islet damage and loss during the islet isolation process. The Nrf2 pathway plays a critical role in protecting the cells against oxidative stress. The aim of this study was to investigate the effect of an Nrf2 activator (dh404) on islet isolation and transplantation in a rodent model. Islet isolation was conducted using Nrf2-deficient and wild-type mice and vehicle-treated and Nrf2 activator (dh404)-treated rats. Islet yield, viability, and Nrf2 pathway activity were determined. An in vivo islet potency test was done. Islet yield and viability in Nrf2-deficient mice was significantly lower compared to wild-type (p < 0.05) mice. Furthermore, administration of dh404 to normal Sprague-Dawley rats enhanced nuclear translocation of Nrf2 and elevated HO-1 expression in the pancreas. Islet yield and viability in dh404-treated rats was significantly higher compared to the vehicle-treated group (p < 0.05). The diabetes cure rate in nude mice with chemically induced diabetes was significantly greater in those transplanted with islets from the dh404-treated group (6/9) than vehicle-treated rats (2/9, p < 0.05). The Nrf2 pathway plays a significant role in protecting islets against stress caused by the isolation process. Pharmacological activation of the Nrf2 pathway significantly increased HO-1 expression, improved islet yield, viability, and function after transplantation.

Dimethyl fumarate ameliorates acute pancreatitis in rodent.

OBJECTIVES: Pancreatitis is a complex inflammatory disorder, ranging from a mild attack, to severe and potentially fatal condition. Dimethyl fumarate (DMF), a potent antioxidant and anti-inflammatory, has been used medicinally for decades. The purpose of this study was to test the hypothesis that treatment with DMF may ameliorate acute pancreatitis (AP) in a rodent model. METHODS: Rats were treated with DMF (25 mg/kg) 24 hours prior to AP induction with l-arginine (3 g/kg). At 72 hours, the pancreas was processed for histology. Serum amylase, lactate dehydrogenase, pancreatic trypsin, and lipid peroxidation product (malondialdehyde) were evaluated. Key cytokines and chemokines in the supernatant of lipopolysaccharide-stimulated splenocytes were also determined. RESULTS: Pancreata from DMF-treated rats showed reductions in the severity of inflammatory cell infiltration, acinar damage, perilobar edema, and cell necrosis. This was associated with significantly lower amylase and malondialdehyde but not lactate dehydrogenase or trypsin levels. The apoptotic pancreatic cells (cleaved caspase 3 positive) were significantly lower in the DMF-treated rats. Lipopolysaccharide-stimulated splenocytes treated with DMF produced a significantly lower amount of key inflammatory mediators. CONCLUSION: Administration of DMF attenuates AP in rats.

Dimethyl fumarate protects pancreatic islet cells and non-endocrine tissue in L-arginine-induced chronic pancreatitis.

BACKGROUND: Chronic pancreatitis (CP) is a progressive disorder resulting in the destruction and fibrosis of the pancreatic parenchyma which ultimately leads to impairment of the endocrine and exocrine functions. Dimethyl Fumarate (DMF) was recently approved by FDA for treatment of patients with multiple sclerosis. DMF's unique anti-oxidant and anti-inflammatory properties make it an interesting drug to test on other inflammatory conditions. This study was undertaken to determine the effects of DMF on islet cells and non-endocrine tissue in a rodent model of L-Arginine-induced CP. METHODS: Male Wistar rats fed daily DMF (25 mg/kg) or vehicle by oral gavage were given 5 IP injections of L-Arginine (250 mg/100 g × 2, 1 hr apart). Rats were assessed with weights and intra-peritoneal glucose tolerance tests (IPGTT, 2 g/kg). Islets were isolated and assessed for islet mass and viability with flow cytometry. Non-endocrine tissue was assessed for histology, myeloperoxidase (MPO), and lipid peroxidation level (MDA). In vitro assessments included determination of heme oxygenase (HO-1) protein expression by Western blot. RESULTS: Weight gain was significantly reduced in untreated CP group at 6 weeks. IPGTT revealed significant impairment in untreated CP group and its restoration with DMF therapy (P <0.05). Untreated CP rats had pancreatic atrophy, severe acinar architectural damage, edema, and fatty infiltration as well as elevated MDA and MPO levels, which were significantly improved by DMF treatment. After islet isolation, the volume of non-endocrine tissue was significantly smaller in untreated CP group. Although islet counts were similar in the two groups, islet viability was significantly reduced in untreated CP group and improved with DMF treatment. In vitro incubation of human pancreatic tissue with DMF significantly increased HO-1 expression. CONCLUSION: Administration of DMF attenuated L-Arginine-induced CP and islet function in rats. DMF treatment could be a possible strategy to improve clinical outcome in patients with CP.

Islet and stem cell encapsulation for clinical transplantation.

Over the last decade, improvements in islet isolation techniques have made islet transplantation an option for a certain subset of patients with long-standing diabetes. Although islet transplants have shown improved graft function, adequate function beyond the second year has not yet been demonstrated, and patients still require immunosuppression to prevent rejection. Since allogeneic islet transplants have experienced some success, the next step is to improve graft function while eliminating the need for systemic immunosuppressive therapy. Biomaterial encapsulation offers a strategy to avoid the need for toxic immunosuppression while increasing the chances of graft function and survival. Encapsulation entails coating cells or tissue in a semipermeable biocompatible material that allows for the passage of nutrients, oxygen, and hormones while blocking immune cells and regulatory substances from recognizing and destroying the cell, thus avoiding the need for systemic immunosuppressive therapy. Despite advances in encapsulation technology, these developments have not yet been meaningfully translated into clinical islet transplantation, for which several factors are to blame, including graft hypoxia, host inflammatory response, fibrosis, improper choice of biomaterial type, lack of standard guidelines, and post-transplantation device failure. Several new approaches, such as the use of porcine islets, stem cells, development of prevascularized implants, islet nanocoating, and multilayer encapsulation, continue to generate intense scientific interest in this rapidly expanding field. This review provides a comprehensive update on islet and stem cell encapsulation as a treatment modality in type 1 diabetes, including a historical outlook as well as current and future research avenues.

Current status of islet encapsulation.

Cell encapsulation is a method of encasing cells in a semipermeable matrix that provides a permeable gradient for the passage of oxygen and nutrients, but effectively blocks immune-regulating cells from reaching the graft, preventing rejection. This concept has been described as early as the 1930s, but it has exhibited substantial achievements over the last decade. Several advances in encapsulation engineering, chemical purification, applications, and cell viability promise to make this a revolutionary technology. Several obstacles still need to be overcome before this process becomes a reality, including developing a reliable source of islets or insulin-producing cells, determining the ideal biomaterial to promote graft function, reducing the host response to the encapsulation device, and ultimately a streamlined, scaled-up process for industry to be able to efficiently and safely produce encapsulated cells for clinical use. This article provides a comprehensive review of cell encapsulation of islets for the treatment of type 1 diabetes, including a historical perspective, current research findings, and future studies.

Salutary effect of pre-treatment with an Nrf2 inducer on ischemia reperfusion injury in the rat liver.

BACKGROUND: Ischemia-reperfusion injury (IRI) is a common phenomenon occurring during liver surgery, transplantation, and trauma. IRI causes oxidative stress which plays a critical role in causing organ damage. The Nrf2 is the master regulator of numerous genes, encoding antioxidant, detoxifying, and cytoprotective molecules. Nrf2 dysfunction has been implicated in the pathogenesis of several inflammatory disorders, cancer, and aging. This study was undertaken to investigate the effect of Nrf2 pathway activator (dh404) on warm liver IRI in a rodent model. METHODS: Ten Sprague-Dawley rats were treated with dh404 or vehicle. Dh404 was dissolved in sesame oil and was given orally (1.5mg/kg) the night before and 5 hours before procedures. Rat livers were subjected to 60 minutes of 70% ischemia followed by 3 hours of reperfusion. Serum ALT and Malondialdehyde (MDA) were determined and liver tissue was processed for histological examination, and determination of apoptosis, myeloperoxidase (MPO) activity, ADP/ATP ratio, and expressions of Nrf2, eNOS, anti-oxidant enzymes, and inflammatory mediators. RESULTS: Serum ALT and MDA levels and tissue MPO activity were significantly lower, expression of the anti-oxidant enzyme, glutamate cysteine ligase were significantly higher, whereas expression of NFkB and COX-2 was unchanged in the dh404-treated group. Although the total Suzuki histology score did not differ significantly, the extent of sinusoidal congestion, vacuolization, and apoptosis was significantly reduced in the dh404 treated compared to the untreated group (P<0.01). CONCLUSIONS: Pre-treatment with dh404 resulted in partial attenuation of hepatic ischemia reperfusion injury in rats.

Role of Oxidative Stress in the Pathogenesis of Pancreatitis: Effect of Antioxidant Therapy.

Oxidative stress plays an important role in the pathogenesis of acute pancreatitis. The exact pathogenesis of pancreatitis remains unknown but several mechanisms related to oxidative and inflammatory stress are implicated. It is reasonable to surmise that antioxidants would play a protective role in ameliorating the deleterious effects of pancreatitis. We have a wealth of data from animal models that reveal a positive correlation between antioxidant drugs and improved outcomes in experimental pancreatitis. Human clinical trials with antioxidants however, have disclosed conflicting results. We review the existing pathogenesis of pancreatitis related to oxidative stress and provide of a review of current trials with antioxidant therapy.

Medium and long-term outcomes after pneumatic dilation or laparoscopic Heller myotomy for achalasia: a meta-analysis.

Recent randomized studies comparing outcomes after pneumatic dilation (PD) and laparoscopic Heller myotomy (LHM) for the treatment of achalasia are conflicting and limited to short-term follow-up. Our meta-analysis compared the long-term durability of these approaches, with the hypothesis that LHM offers superior long-term remission compared with PD. We identified 36 studies published between 2001 and 2011 with at least 5 years of follow-up. Those studies describing PD included 3211 patients (mean age, 49.8 y). For PD, the mean 5-year remission rate was 61.9% and the mean 10-year remission rate was 47.9%. Overall, 1526 patients (mean age, 46.3 y) were treated with LHM; 83% received a fundoplication. In contrast, the mean 5- and 10-year remission rates after LHM were 76.1% and 79.6%, respectively. Finally, the perforation rate for LHM was twice that of PD (4.8% vs. 2.4%; P<0.05). We conclude that despite a higher frequency of perforation, LHM affords greater long-term durability.

Presentation, diagnosis, and treatment of oesophageal motility disorders.

Whilst the current treatment of achalasia is well understood, the management of other oesophageal disorders is still debated, as these are rare and the literature on their clinical presentation and management is scarce. The following review describes the clinical presentation of oesophageal motility disorders, gives an overview of their diagnosis in light of the new advances in oesophageal motility testing, and provides an evidence-based approach to their management with different forms of treatment (medical, endoscopic, and minimally invasive).

The addition of a nurse practitioner to an inpatient surgical team results in improved use of resources.

BACKGROUND: Resident work hour restrictions and changes in reimbursement may lead to an adverse effect on the continuity of care of a patient after discharge. This study analyzes whether adding a nurse practitioner (NP) to a busy inpatient surgery service would improve patient care after discharge. METHODS: In 2007, a NP joined a team of 3 surgery attendings. She coordinated the discharge plan and communicated with patients after discharge. We reviewed the records of patients 1 year before (N = 415) and 1 year after (N = 411) the NP joined the team. The discharge courses of the patients were reviewed, and an unnecessary emergency room (ER) visit was defined as an ER visit that did not result in an inpatient admission. RESULTS: The 2 groups were statistically similar with regard to age, race, acuity of the operation, duration of hospital stay, and hospital readmissions. Telephone communication between nurses and discharged patients was 846 calls before the NP and 1,319 calls after the NP, representing an increase of 64% (P < .0001). Visiting nurse, physical therapy, or occupational therapy services were rendered to only 25% of patients before the NP compared to 39% after (P < .0001). There were more unnecessary ER visits before the NP (103/415; 25%) compared to after (54/411; 13%) (P = .001). CONCLUSION: Adding a NP to our inpatient surgery service led to an overall improvement in the use of resources and a 50% reduction in unnecessary ER visits. This study shows that the addition of a NP not only improves continuity of care on discharge but also has the potential to yield financial benefits for the hospital.